This invention relates to a folding device and particularly to a device which folds a web of continuous paper along a weakened perforation or fold line which extends longitudinally along the web. The web folding device is used in combination with a web processing machine which draws the web from the web folding device in a downstream path of travel. There are many types of business correspondence which are prepared by computer and generated by means of a continuous form. The continuous form is folded along a longitudinal weakened fold line prior to being either burst apart or cut such that the individual pieces of correspondence can be inserted in an envelope for mailing. Typical examples of such applications are insurance premium notices, mortgage payment notices, and other payment forms. With this type of correspondence, it is intended that the recipient keep one part of the form, separate and return the other part to the sender. The continuous web is provided with a longitudinal fold line or perforation line which is generally the fold line for the form.
Several prior devices have attempted to fold the continuous web along the longitudinal weakened fold line. One example is illustrated in U.S. Pat. No. 4,395,255 issued July 26, 1983 to Branecky, et al. This device provides the folding a web along a longitudinal fold line by drawing the web over a drag member longitudinally extending across the path of travel of the unfolded web. The web then passes around several rollers and exits from the folding device. However, this device still tends to cause the web to tear along the horizontal perforations as it is drawn through the web folding device. Furthermore, this device does not provide for feeding the web from either side of the device and can fold the web in only one way with the web on one side of the fold line always being folded on top of the other side of the web. Branecky attempts to compensate for the possibility of tearing the web by mounting one of the lower rollers transverse to the drag member at an angle of approximately 95.degree. with respect to a vertical plane passing through the drag member. However, even with this angular mounting, the entire force of pulling the web through the web folding apparatus must be applied to the web itself. Therefore, the web and the perforations must have sufficient strength to allow the web to be drawn through the web folding apparatus without tearing and yet still be perforated in such a manner that it can be easily burst by the bursting machine.
Another prior art device is illustrated in U.S. Pat. No. 3,356,557 issued Dec. 5, 1967 to Enskat. In this device a web of paper is fed from a first roller to a second roller which is oriented at right angles to the first roller and spaced above it. The web is folded while it is traveling between the rollers. There is not any means to aid or guide the web as it is folded. Furthermore, there are not any provisions for aiding or guiding the web as it is folded. There are not any means to alleviate or minimize the forces on the web to reduce the possibility of the web inadvertently tearing as it is being folded or passing through the web folding device.
None of the devices shown in the prior art illustrate or suggest a web folding device which can be adapted to fold a web along a fold line such that either side of the web along the fold line can be folded over the other side. Thus, none of these prior art devices can provide for either portion to become the top portion after the web is folded. This presents an obvious shortcoming and limitation in prior devices. If addresses or other information must be placed in a predetermined orientation after folding, the continuous web must be pre-printed in a certain way. If the web can be folded with the web on either side of the fold line oriented on top, the user has greater latitude and options in generating and working with the web.
Accordingly, an object of this invention is to provide an improved web folding apparatus for folding an unfolded web longitudinally along a weakened fold line, the web folding device designed for use in combination with a web processing machine which draws the web from the web folding device.
Another object is to provide a web folding device which alleviates some of the stresses on the web as it is folded to minimize the possibility of the web inadvertently tearing. A related object is to provide an improved web folding device which aids in feeding the web in a downstream path of travel as it is being folded.
Yet another object is to provide a web folding device which aids in feeding the web as it is being folded by means of a motor-driven roller which causes a belt to contact and drive the web only when the web processing machine is drawing the web.
Still another object is to provide a web folding device which can accommodate receiving the web from either of two sides of the device such that either side of the web adjacent the longitudinal weakened fold line can become the top surface of the web after it is folded.